Using a tectonic history model for petroleum system analysis
| Exploring for Oil and Gas Traps | |
| |
| Series | Treatise in Petroleum Geology |
|---|---|
| Part | Critical elements of the petroleum system |
| Chapter | Sedimentary basin analysis |
| Author | John M. Armentrout |
| Link | Web page |
| Store | AAPG Store |
A model of the tectonic history of a basin provides a regional framework for understanding the development of essential elements and processes of the petroleum systems in a basin. A basin such as the Gulf of Mexico can have more than one petroleum system; therefore, the evolution of elements and processes can have an impact on different petroleum systems at the same time or at different times, depending on the events of each tectonostratigraphic phase.
Example from GOM basin
The tectonic history of the GOM basin provides the regional framework for mapping elements and processes of the petroleum systems within the High Island–East Breaks area. Following is a summary of the tectonic history of the basin.
- Within the GOM rift basin, major areas of transitional crust formed between continental crust and Late Jurassic oceanic crust. Middle Jurassic crustal attenuation associated with the transitional crust formed sags in which evaporites were deposited.
- During the Late Jurassic and Early Cretaceous, thermal subsidence of the basin center and relatively high sea level formed extensive carbonate platforms along the basin margin and sediment starvation of the basin center. Organic-rich, oil-prone marine sediments were deposited within low-oxygen environments of this sediment-starved basin. These rocks later became the primary source of oil and gas—some of which migrated to and is stored within porous zones of the carbonate platforms.
- Late Cretaceous and Cenozoic siliciclastic sedimentation formed thick, prograding prisms over the transitional crust and differentially loaded the Late Jurassic salt. The deformed salt created anticlinal highs bordering sediment-filled synclinal lows, which continued to subside and provide sediment transport pathways downslope. The deformation of the salt and associated sediments formed both structural and stratigraphic traps within the siliciclastic section. Sedimentary burial and salt-thickness/mobility patterns affect hydrocarbon generation due to variations in the thermal conductivity of salt. Intersecting fault trends, one paralleling northwest–southeast-trending basement faults and a second associated with depositional strike-oriented growth faults, provide vertical avenues for migration of hydrocarbons from deeply buried mature Mesozoic [[source rocks]] upward into reservoir rocks of Jurassic, Cretaceous, and Cenozoic age.
Areas of maximum sediment accumulation and consequent salt deformation were controlled by areas of maximum sediment input and sea-floor subsidence.
See also
- Assessing the impact of tectonics
- Making regional tectonic maps
- Making regional structural cross sections
- Determining plate tectonic setting and history
- Determining tectonostratigraphic history
External links
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